P. aeruginosa and Acinetobacter spp. are known to be commons pathogens of nosocomial infections, mainly in intensive care units. Moreover, their clinical importance is also due to intrinsic and acquired resistance to many antimicrobials, which are cause of development of multidrug-resistance and pandrug-resistance phenotypes. The proposal of this study is to investigate resistance mechanism to antimicrobial as loss of porins (channels transmembrane proteins), overexpression of efflux pumps and genetic element carrying resistance genes as integrons. Strains isolated from hospitalized patients at University Hospital of Juiz de Fora Federal University, from 2003 to 2006, are going to be studied. The susceptibility profiles to antimicrobial of these strains are going to be determined and applied to classify then in different resistance levels. The clonal variability of strains is going to be investigated by PFGE. Class 1, 2 and 3 integrons are going to be detected by hybridization with specific probes and cassettes genes carried by these integrons are going to be characterized by PCR, RFLP and DNA sequencing. Bacterial outer membrane protein will be extracted and shared by electrophoresis for verifying loss of porins. Furthermore, efflux pumps overexpression is going to be investigated by kinetics of ethidium bromide accumulation in the cells and real time RT-PCR. The data generated by the research of resistance mechanisms associated to susceptibility profile to antimicrobial and PFGE can be useful to evaluate the involvement of these resistance mechanisms in multidrug-resistance phenotypes among P. aeruginosa and Acinetobacter spp. strains.
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